/**
 * @author ZhangHuihua@msn.com
 *         ---------------------------------------------------------- These
 *         functions use the same 'format' strings as the
 *         java.text.SimpleDateFormat class, with minor exceptions. The format
 *         string consists of the following abbreviations: Field | Full Form |
 *         Short Form -------------+--------------------+-----------------------
 *         Year | yyyy (4 digits) | yy (2 digits), y (2 or 4 digits) Month | MMM
 *         (name or abbr.)| MM (2 digits), M (1 or 2 digits) | NNN (abbr.) | Day
 *         of Month | dd (2 digits) | d (1 or 2 digits) Day of Week | EE (name) |
 *         E (abbr) Hour (1-12) | hh (2 digits) | h (1 or 2 digits) Hour (0-23) |
 *         HH (2 digits) | H (1 or 2 digits) Hour (0-11) | KK (2 digits) | K (1
 *         or 2 digits) Hour (1-24) | kk (2 digits) | k (1 or 2 digits) Minute |
 *         mm (2 digits) | m (1 or 2 digits) Second | ss (2 digits) | s (1 or 2
 *         digits) AM/PM | a | NOTICE THE DIFFERENCE BETWEEN MM and mm! Month=MM,
 *         not mm! Examples: "MMM d, y" matches: January 01, 2000 Dec 1, 1970
 *         Nov 20, 00 "M/d/yy" matches: 01/20/00 9/2/00 "MMM dd, yyyy hh:mm:ssa"
 *         matches: "January 01, 2000 12:30:45AM"
 *         ----------------------------------------------------------
 */
( function() {
    var MONTH_NAMES = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December', 'Jan', 'Feb', 'Mar',
        'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec');
    var DAY_NAMES = new Array('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat');
    function LZ(x) {
        return ( x < 0 || x > 9 ? "": "0" ) + x
    }

    /**
     * formatDate (date_object, format) Returns a date in the output format
     * specified. The format string uses the same abbreviations as in
     * parseDate()
     *
     * @param {Object}
     *            date
     * @param {Object}
     *            format
     */
    function formatDate(date, format) {
        format = format + "";
        var result = "";
        var i_format = 0;
        var c = "";
        var token = "";
        var y = date.getYear() + "";
        var M = date.getMonth() + 1;
        var d = date.getDate();
        var E = date.getDay();
        var H = date.getHours();
        var m = date.getMinutes();
        var s = date.getSeconds();
        var yyyy, yy, MMM, MM, dd, hh, h, mm, ss, ampm, HH, H, KK, K, kk, k;
        // Convert real date parts into formatted versions
        var value = {};
        if (y.length < 4 ) {
            y = "" + ( y - 0 + 1900 );
        }
        value.y = "" + y;
        value.yyyy = y;
        value.yy = y.substring(2, 4);
        value.M = M;
        value.MM = LZ(M);
        value.MMM = MONTH_NAMES[M - 1];
        value.NNN = MONTH_NAMES[M + 11];
        value.d = d;
        value.dd = LZ(d);
        value.E = DAY_NAMES[E + 7];
        value.EE = DAY_NAMES[E];
        value.H = H;
        value.HH = LZ(H);
        if (H == 0 ) {
            value.h = 12;
        } else {
            if (H > 12) {
                value.h = H - 12;
            } else {
                value.h = H;
            }

        }
        value.hh = LZ(value.h);
        if (H > 11 ) {
            value.K = H - 12;
        } else {
            value.K = H;
        }
        value.k = H + 1;
        value.KK = LZ(value.K);
        value.kk = LZ(value.k);
        if (H > 11 ) {
            value.a = "PM";
        } else {
            value.a = "AM";
        }
        value.m = m;
        value.mm = LZ(m);
        value.s = s;
        value.ss = LZ(s);
        while (i_format < format.length) {
            c = format.charAt(i_format);
            token = "";
            while ( ( format.charAt(i_format) == c ) && ( i_format < format.length )) {
                token += format.charAt(i_format++);
            }
            if (value[token] != null ) {
                result += value[token];
            } else {
                result += token;
            }
        }
        return result;
    }
    function _isInteger(val) {
        return ( new RegExp(/^\d+$/).test(val) );
    }
    function _getInt(str, i, minlength, maxlength) {
        for (var x = maxlength; x >= minlength; x--) {
            var token = str.substring(i, i + x);
            if (token.length < minlength ) {
                return null;
            }
            if (_isInteger(token) ) {
                return token;
            }
        }
        return null;
    }

    /**
     * parseDate( date_string, format_string ) This function takes a date string
     * and a format string. It matches If the date string matches the format
     * string, it returns the date. If it does not match, it returns 0.
     *
     * @param {Object}
     *            val
     * @param {Object}
     *            format
     */
    function parseDate(val, format) {
        val = val + "";
        format = format + "";
        var i_val = 0;
        var i_format = 0;
        var c = "";
        var token = "";
        var token2 = "";
        var x, y;
        var now = new Date(1970, 0, 1);
        var year = now.getYear();
        var month = now.getMonth() + 1;
        var date = 1;
        var hh = now.getHours();
        var mm = now.getMinutes();
        var ss = now.getSeconds();
        var ampm = "";
        while (i_format < format.length) {
            // Get next token from format string
            c = format.charAt(i_format);
            token = "";
            while ( ( format.charAt(i_format) == c ) && ( i_format < format.length )) {
                token += format.charAt(i_format++);
            }
            // Extract contents of value based on format token
            if (token == "yyyy" || token == "yy" || token == "y" ) {
                if (token == "yyyy" ) {
                    x = 4;
                    y = 4;
                }
                if (token == "yy" ) {
                    x = 2;
                    y = 2;
                }
                if (token == "y" ) {
                    x = 2;
                    y = 4;
                }
                year = _getInt(val, i_val, x, y);
                if (year == null ) {
                    return 0;
                }
                i_val += year.length;
                if (year.length == 2 ) {
                    if (year > 70 ) {
                        year = 1900 + ( year - 0 );
                    } else {
                        year = 2000 + ( year - 0 );
                    }
                }
            } else if (token == "MMM" || token == "NNN" ) {
                month = 0;
                for (var i = 0; i < MONTH_NAMES.length; i++) {
                    var month_name = MONTH_NAMES[i];
                    if (val.substring(i_val, i_val + month_name.length).toLowerCase() == month_name.toLowerCase() ) {
                        if (token == "MMM" || ( token == "NNN" && i > 11 ) ) {
                            month = i + 1;
                            if (month > 12 ) {
                                month -= 12;
                            }
                            i_val += month_name.length;
                            break;
                        }
                    }
                }
                if ( ( month < 1 ) || ( month > 12 ) ) {
                    return 0;
                }
            } else if (token == "EE" || token == "E" ) {
                for (var i = 0; i < DAY_NAMES.length; i++) {
                    var day_name = DAY_NAMES[i];
                    if (val.substring(i_val, i_val + day_name.length).toLowerCase() == day_name.toLowerCase() ) {
                        i_val += day_name.length;
                        break;
                    }
                }
            } else if (token == "MM" || token == "M" ) {
                month = _getInt(val, i_val, token.length, 2);
                if (month == null || ( month < 1 ) || ( month > 12 ) ) {
                    return 0;
                }
                i_val += month.length;
            } else if (token == "dd" || token == "d" ) {
                date = _getInt(val, i_val, token.length, 2);
                if (date == null || ( date < 1 ) || ( date > 31 ) ) {
                    return 0;
                }
                i_val += date.length;
            } else if (token == "hh" || token == "h" ) {
                hh = _getInt(val, i_val, token.length, 2);
                if (hh == null || ( hh < 1 ) || ( hh > 12 ) ) {
                    return 0;
                }
                i_val += hh.length;
            } else if (token == "HH" || token == "H" ) {
                hh = _getInt(val, i_val, token.length, 2);
                if (hh == null || ( hh < 0 ) || ( hh > 23 ) ) {
                    return 0;
                }
                i_val += hh.length;
            } else if (token == "KK" || token == "K" ) {
                hh = _getInt(val, i_val, token.length, 2);
                if (hh == null || ( hh < 0 ) || ( hh > 11 ) ) {
                    return 0;
                }
                i_val += hh.length;
            } else if (token == "kk" || token == "k" ) {
                hh = _getInt(val, i_val, token.length, 2);
                if (hh == null || ( hh < 1 ) || ( hh > 24 ) ) {
                    return 0;
                }
                i_val += hh.length;
                hh--;
            } else if (token == "mm" || token == "m" ) {
                mm = _getInt(val, i_val, token.length, 2);
                if (mm == null || ( mm < 0 ) || ( mm > 59 ) ) {
                    return 0;
                }
                i_val += mm.length;
            } else if (token == "ss" || token == "s" ) {
                ss = _getInt(val, i_val, token.length, 2);
                if (ss == null || ( ss < 0 ) || ( ss > 59 ) ) {
                    return 0;
                }
                i_val += ss.length;
            } else if (token == "a" ) {
                if (val.substring(i_val, i_val + 2).toLowerCase() == "am" ) {
                    ampm = "AM";
                } else if (val.substring(i_val, i_val + 2).toLowerCase() == "pm" ) {
                    ampm = "PM";
                } else {
                    return 0;
                }
                i_val += 2;
            } else {
                if (val.substring(i_val, i_val + token.length) != token ) {
                    return 0;
                } else {
                    i_val += token.length;
                }
            }
        }
        // If there are any trailing characters left in the value, it doesn't
        // match
        if (i_val != val.length ) {
            return 0;
        }
        // Is date valid for month?
        if (month == 2 ) {
            // Check for leap year
            if ( ( ( year % 4 == 0 ) && ( year % 100 != 0 ) ) || ( year % 400 == 0 ) ) { // leap
                // year
                if (date > 29 ) {
                    return 0;
                }
            } else {
                if (date > 28 ) {
                    return 0;
                }
            }
        }
        if ( ( month == 4 ) || ( month == 6 ) || ( month == 9 ) || ( month == 11 ) ) {
            if (date > 30 ) {
                return 0;
            }
        }
        // Correct hours value
        if (hh < 12 && ampm == "PM" ) {
            hh = hh - 0 + 12;
        } else if (hh > 11 && ampm == "AM" ) {
            hh -= 12;
        }
        return new Date(year, month - 1, date, hh, mm, ss);
    }
    Date.prototype.formatDate = function(dateFmt) {
        return formatDate(this, dateFmt);
    };
    String.prototype.parseDate = function(dateFmt) {
        if (this.length < dateFmt.length ) {
            dateFmt = dateFmt.slice(0, this.length);
        }
        return parseDate(this, dateFmt);
    };

    /**
     * replaceTmEval("{1+2}-{2-1}")
     */
    function replaceTmEval(data) {
        return data.replace(RegExp("({[A-Za-z0-9_+-]*})", "g"), function($1) {
            return eval('(' + $1.replace(/[{}]+/g, "") + ')');
        });
    }
    /**
     * dateFmt:%y-%M-%d %y-%M-{%d+1} ex: new Date().formatDateTm('%y-%M-{%d-1}')
     * new Date().formatDateTm('2012-1')
     */
    Date.prototype.formatDateTm = function(dateFmt) {
        var y = this.getFullYear();
        var m = this.getMonth() + 1;
        var d = this.getDate();
        var sDate = dateFmt.replaceAll("%y", y).replaceAll("%M", m).replaceAll("%d", d);
        sDate = replaceTmEval(sDate);
        var _y = 1970, _m = 0, _d = 1;
        var aDate = sDate.split("-");
        if (aDate.length > 0 ) {
            _y = aDate[0];
        }
        if (aDate.length > 1 ) {
            _m = aDate[1] - 1;
        }
        if (aDate.length > 2 ) {
            _d = aDate[2];
        }
        return new Date(_y, _m, _d).formatDate('yyyy-MM-dd');
    };
} )();